How severe is CVE-2021-45909?

CVE-2021-45909 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-45909 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-45909?

CVE-2021-45909 primarily affects Gif2apng Project Gif2apng. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-45909?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-45909 published?

CVE-2021-45909 was published on 2021-12-28 and last updated on 2026-06-17.

CVE-2021-45909

CVE-2021-45909 is a high-severity vulnerability in Gif2apng Project Gif2apng with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Gif2apng Project Gif2apng
Published: 2021-12-28
Last modified: 2026-06-17

Description

An issue was discovered in gif2apng 1.9. There is a heap-based buffer overflow vulnerability in the DecodeLZW function. It allows an attacker to write a large amount of arbitrary data outside the boundaries of a buffer.

Frequently asked questions

What is CVE-2021-45909?: An issue was discovered in gif2apng 1.9. There is a heap-based buffer overflow vulnerability in the DecodeLZW function. It allows an attacker to write a large amount of arbitrary data outside the boundaries of a buffer.
How severe is CVE-2021-45909?: CVE-2021-45909 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-45909 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-45909?: CVE-2021-45909 primarily affects Gif2apng Project Gif2apng. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-45909?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-45909 published?: CVE-2021-45909 was published on 2021-12-28 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:gif2apng_project:gif2apng:1.9:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

More vulnerabilities in Gif2apng Project Gif2apng

CVE-2021-45911 — High (CVSS 7.8): An issue was discovered in gif2apng 1.9. There is a heap-based buffer overflow in the main function. It allows an…
CVE-2021-45910 — High (CVSS 7.8): An issue was discovered in gif2apng 1.9. There is a heap-based buffer overflow within the main function. It allows an…
CVE-2021-45908 — High (CVSS 7.8): An issue was discovered in gif2apng 1.9. There is a stack-based buffer overflow involving a while loop. An attacker has…
CVE-2021-45907 — High (CVSS 7.8): An issue was discovered in gif2apng 1.9. There is a stack-based buffer overflow involving a for loop. An attacker has…

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